You'll find all sorts of waitressing jobs (the title is "server" in a lot of Idaho, no idea why, but I've been sternly corrected so thought I'd give you a head's up). There are also many small businesses, many even being "mom-'n'-pop". You'll find those Downtown and North End. A lot of South, East, and West is bought up by strip malls, most of which contain chains, but you'll find the occasional locally owned restaurant in those. Really, I'd say a lot of locally owned businesses exist along Overland in the stretch between I-84 junction and Vista, plus on some of Vista. There's a few other outliers like Trolley House on Warm Springs, but you'll have your best luck looking through the phone book and Google Earth.
One thing you should know about Idaho is that it's a right-to-work state. This means that employers of professions that receive tips have the option of paying less than minimum wage. Many in Boise pay well due to the higher cost of living, but some will pay less, especially small businesses who need a competitive edge in their prices. It would not be far-fetched to expect about $2 less than minimum wage.
People who are aware of this fact tip much better. Having worked several jobs in the food industry myself during my time in Idaho, I tip
at least 20% in right-to-work states unless my service is downright rude or negligent (and with negligence, only if they don't appear over-worked). If there's a classy bar or a chef, I go above and beyond in my tip. Really, tipping is a devout practice for anyone in Idaho who isn't an unemployed, oblivious, self-centered brat. Unfortunately, you'll find those everywhere, along with the dumba$$es who, against even the most glaring evidence, insist that 15% is the "accepted tradition".

Those ilk are no more prevalent in Idaho than anywhere else, though. In fact, from my experience I'd argue they're less prevalent, but there's no way to promise that.